Russia destroyed a portion of an apartment building while occupants slept on Friday in missile attacks near Ukraine’s port of Odesa, killing at least 21 people, according to officials, only hours after Russian soldiers abandoned the Black Sea stronghold of Snake Island.

Locals in the resort hamlet of Serhiivka assisted employees in sorting through the wreckage of the nine-story apartment building, a chunk of which was entirely demolished in the early-morning walkout.

Serhiy Bratchuk, spokesperson for the Odesa regional government, reported 21 deaths, including a 12-year-old kid.

Among those killed was a member of the Children’s Rehabilitation Center established up in the resort by Ukraine’s neighbor Moldova. Five more people were hurt.

“These peaceful people made the days of the children of Moldova more beautiful, they took care of their rehabilitation with great love and devotion,” Moldovan Health Minister Alla Nemerenko said on her Facebook page.

The strike happened just four days after Russia launched an attack on a packed retail mall in central Ukraine, killing at least 19 people.

Ukraine claims that Moscow has expanded its long-range assaults, targeting civilian targets distant from the frontlines, committing war crimes. Russia claims to have targeted military installations.

Since Russia’s invasion of Ukraine on February 24, thousands of people have been slain. Russia describes the invasion as a “special operation” to eliminate nationalists. Ukraine and its Western supporters claim it is an unprovoked aggression war.